Centralized computer systems with multiple independent terminal systems for accessing the centralized computer systems were once the dominant computer system architecture. These centralized computer systems were initially very expensive mainframe or mini-computer systems that were shared by multiple computer users. Each of the computer system users accessed the centralized computer systems using a computer terminal system coupled to the centralized computer systems.
In the late 1970s and early 1980s, semiconductor microprocessors and memory devices allowed for the creation of inexpensive personal computer systems. Personal computer systems revolutionized the computing industry by allowing each individual computer user to have access to a full computer system without having to share the computer system with any other computer user. Each personal computer user could execute their own software applications and any problems with the computer system would only affect that single personal computer system user.
Although personal computer systems have become the dominant form of computing in the modern world, there has been a resurgence of the centralized computer system model wherein multiple computer users access a single server system using modern terminal systems that include high-resolution graphics. Computer terminal systems can significantly reduced computer system maintenance costs since computer terminal users cannot easily introduce computer viruses into the main computer system or load other unauthorized computer programs. Terminal based computing also allows multiple users to easily share the same set of software applications.
Modern personal computer systems have become increasingly powerful in the decades since the late 1970's personal computer revolution. Modern personal computer systems are now more powerful than the shared mainframe and mini-computer systems of the 1970's. In fact, modern personal computer systems are so powerful that the vast majority of the computing resources in modern personal computer systems generally sit idle when a typical computer user uses a modern personal computer system. Thus, personal computer systems can now easily serve multiple computer users.